Dengue virus (DENV) infections are an emerging problem, causing disease in tropical and subtropical countries, including the U.S, with recent outbreaks in Texas, Hawaii and Florida. An increase in the average age of DENV related hospitalizations has been globally recognized with adult disease more commonly recognized, but prospective clinical studies that characterize dengue illness in both children and adults are lacking. Dengue hemorrhagic fever (DHF), a more severe clinical manifestation of DENV infection, has been classified by the WHO into four grades of severity with minimal criteria of capillary leakage and thrombocytopenia. The WHO released revised guidelines for the diagnosis of